Use of cyclic amidine polymers as corrosion inhibitors

ABSTRACT

THE USE OF CYCLIC AMIDINE POLYMERS AS CORROSION INHIBITORS. THESE POLYMERS ARE FORMED (1) BY REACTING CYANOHYDRINS WITH (2) CYCLIC AMIDINE-FORMING POLYAMINES TO FORM POLYAMINONITRILES; AND BY FURTHER REACTING THESE POLYAMINONITRILES INTERMOLECULARLY OR WITH A POLYAMINE UNDER CYCLIC AMIDINE-FORMING CONDITIONS TO FORM THE POLYMERS.

United States Patent 3,669,612 USE OF CYCLIC AMIDINE POLYMERS AS CORROSION INHIBITORS Robert R. Annand, St. Louis, and Derek Redmore, Ballwin, Mo., and Brian M. Rushton, Williamsville, N.Y., assignors to Petrolite Corporation, Wilmington, Del. No Drawing. Original application Oct. 22, 1965, Ser. No. 502,636, now Patent No. 3,531,496, dated Sept. 29, 1970. Divided and this application May 15, 1970, Ser. No. 37,857

Int. Cl. C23f 11/00, 11/08 US. CI. 21-25 10 Claims ABSTRACT OF THE DISCLOSURE The use of cyclic amidine polymers as corrosion inhibitors. These polymers are formed (1) 'by reacting cyanohydrins with (2) cyclic amidine-forming polyamines to form polyaminonitriles; and by further reacting these polyaminonitriles intermolecularly or with a polyamine under cyclic amidine-forming conditions to form the polymers.

These are illustrated by the following reactions which are usually carried out in the presence of a cyanide ion.

11.0:0 HCN HO-CH2CN OH H amalgam-0:0 non omomcmo ice The reaction of a carbonyl group with HCN to form cyanohydrins is a general reaction for aliphatic ketones having at least one methyl group attached to the carbonyl group. It is particularly applicable to aldehydes, cyclic ketones, etc. Thus, the carbonyl compounds may be aliphatic, aromatic, heterocyclic, cycloaliphatic, combinations thereof such as alkaryl, alkylheterocyclic, etc.; may be derived from monoor poly-carbonyls; may be aldehydes, ketones, and the like.

We have now found that cyanohydrins react with cyclic amidine-forming polyamines, which are capable of forming polymers, to form a cyclic amidine polymer. These are illustrated by the following reactions:

which further reacts to yield a polymer having the following un1t:

Analogous polymers having a tetrahydropyrimidine group are formed from polyamines having three carbons between the amino groups, for example, of the formula It is noted that the above reaction is an intermolecular reaction of one molecular species. In addition two moles of the cyanohydrin can also react with one mole 05f polyamine in the following manner:

This dinitrile is capable of further'reaction with a cyclic amidine forming amine capable of forming a polymer to form the cyclic amidine polymers of this invention as illustrated by the following reactions:

Analogous polymers are formed from polyamines having three carbons between the amino groups to yield a tetrahydropyrimidine group, for example, of the formula R R ((BH2)3 (Hz)3-I In addition to employing the cyanohydrin, a derivative thereof may be employed. For example, a volatile amine, such as a dialkylamine, may be reacted with the cyanohydrin to form an amine derivative and this more volatile amine component may be replaced by the higher boiling polyamines employed in this invention. This may be illustrated by the following reactions:

which can be polymerized with a cyclic amidine forming polyamine to yield the polymer of this invention.

The polymers of this invention may be illustrated, for example, by the following general formulae:

where R and R (which may be the same or difierent) are hydrogens or a substituted group, for example, alkyl, aryl, cycloalkyl, heterocyclic, etc. or joined in a cyclic structure such as in a cycloalkyl ring, etc.; preferably in the instance where both R and R are substituted in a noncyclic configuration that one of the Rs is preferably methyl; A is for example an alkylene group having 2-3 carbons in the main chain (but may also be branched); Z is the moiety of the cyclic amidine forming amine, for example A or (A x where n=l or greater, for example 1-5 or more; n=O-5 or more; the number of carbons in the R or R groups can range, for example, from l-l8 or more carbons.

These polymers have a cyclic amidine group in the main chain of the polymer as contrasted to a cyclic amidine pendant group. They are formed, for example, by reacting (l) a cyanohydrin with one mole of a cyclic amidine-forming polyamine so that the resulting compound has both a nitrile and a cyclic amidine-forming moiety; (2) a dinitrile derived from a cyanohydrin and a cyclic amidine-forming polyamine which is di-functional in relation to its cyclic amidine-forming function, i.e. having two pairs of cyclic amidine-forming groups, i.e.

NHz LA Jn where n is an integer 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.,

and A is an alkylene group, provided that the polyamine contains an alkylene moiety of a cyclic-amidine forming group, i.e., a group having a group.

One or more of the hydrogens on the CH groups may be substituted for example, by such groups as alkyl groups, for example, methyl, ethyl, etc. Examples of A include etc.

Examples of polyamines include the following: ethylene diamine, propylene diamine, diethylene triamine, dipropylene triamine, triethylene tetramine, tripropylene tetramine, tetraethylene pentamine, tetrapropylene pentamine, polyalkyleneimines, i.e. the higher molecular weight amines derived from alkyleneimine such as polyethyleneimines, polypropyleneimines, etc. Mixtures of the above polyamine amines and those polyamines containing both ethylene and propylene groups, for example etc., can be employed.

Some of the N-groups may be substituted (provided the polyamine is cyclic-amidine forming), for example, with hydrocarbon groups such as alkyl groups, etc.

The reaction of the polyamine with the cyanohydrin takes place quite readily at ambient temperatures, for example, at about 20-80 C. or higher, but preferably at about 30-50 C. After the addition of one reactant to the other, the reaction mixture is heated at a temperature sufiiciently high to remove the water formed during the reaction. Reduced pressure may be employed, if desired, to remove water and unreacted components. An azeotrope agent may be employed. Optimum temperature and conditions will of course depend upon the particular amine employed and the particular product desired.

The polyamine is reacted so that a residual cyclic amidine-forming group remains or until a dinitrile is formed. Stoichiometric amounts of reactants can be employed. However, in preparing the monocyano product it is preferred to employ an excess of polyamine. In the case of the dicyano product the reaction proceeds so readily that no excess of either reactant is generally employed.

The mono-cyano cyclic amidine-forming polyamine or the dicyano polyamine is then intermolecularly reacted with itself, or with a polyamine, under cyclic amidineforming conditions to form the polymer of this invention. It is preferable that a catalyst be employed to speed up the reaction. Among such catalysts are organic and inorganic salts such as sulfonic acids, etc. However, it is preferred to use sulfur compounds such as H S, thioacids, thioamides, thioketones, thiourea, dithiobiurette, etc., as catalysts.

In general the temperature of polymerization will vary with the particular reactants, catalysts, etc. In general, the reaction is carried out from about 75 to 200 C., such as from about to 175 C., but preferably from about to C. Optimum temperatures will vary with the particular system.

The molecular weight of the polymer can vary Widely depending on various factors such as reactants, conditions, ultimate uses, etc. In general, the polymer may contain about 2 to 100 or more units, such as 5-50, for example, 8-40, but polymers having 4-15 are advantageously employed for the uses disclosed herein.

In addition, to the basic form of these polymers, one can, in certain instances, prepare salts or quaternaries, either with organic or inorganic acids or quaternizing agents such as benzyl halides, alkyl halides, etc., dihalides such as al'kylene dihalides, xylylene dihalides, alkylene ether dihalides such as (XCH CHQ O, etc. Being basic the cyclic amidine unit readily forms salts, including diand polysalts.

Examples of acids which can be employed to form salts include HCl, H 80 H PO hydrocarbon sulfonic acids, acetic acid, oxalic acid, maleic acid, oleic acid, abietic acid, naphthenic acid, rosin, benzoic acid, phthalic acid, diglycollic acid, etc.

The following examples are presented for purposes of illustration and not of limitation.

EXAMPLE 1 To a stirred solution of ethylene diamine (120 g.; 2 moles) in benzene (200 ml.) was added acetone cyanohydrin (42.5 g.; 0.5 mole) dropwise during 30 minutes. An exothermic reaction took place. The apparatus was fitted with a Dean and Stark trap and the mixture heated under reflux for 2 hours during which time 9 mls. (0.5 mole) of water was collected. Benzene and excess ethylene diamine were removed in vacuo to yield 54.2 g. (86%) of N-(B-aminoethyl) a-amino isobutyronitrile as a pale yellow oil. Analysis as follows was obtained: C H N requires (percent) total N, 33, found 31.0; basic N, 22.0, found 20.0. Molecular wt. 127, found (osometry) 124.

To the aminonitrile (54 g.) was added thiourea (750 mg.) and the mixture heated at 140-160 for hours. After the addition of 250 mg. more thiourea heating was continued for 3 hours at which time ammonia evolution had ceased. The product, a dark viscous oil, was very soluble in water, methanol and acetone and virtually insoluble in ether and benzene. The molecular weight of the crude product was 350 by osmometry. The infrared spectrum of of the product had peaks at 2.9 (NH) and 6.2 (C=N) indicating a cyclic amidine structure. The polymer has the following formula EXAMPLE 2 Acetone cyanohydrin (425 g.; 5 moles) was added dropwise with stirring to ethylene diamine (300 g.; 5 moles) during one hour. The reaction was cooled in an ice bath to maintain a temperature of 30-35 The mixture was heated and water (100 ml.) was removed by distillation. Thionrea (5 g.) was added and the mixture was heated to 180. Ammonia evolution was copious. After 5 hours more thiourea (2 g.) was added and heating continued for 3 more hours when no more ammonia was evolved. The product showed an identical infrared spectrum with that from Example 1.

EXAMPLE 3 Acetone cyanohydrin (85 g.; 1 mole) was reacted with 25% aqueous dimethylamine (180 g.; 1 mole) to .produce N,N-dimethyl 2-aminoisobutyronitrile 81 g.; 72%, B.P. 723/48 mm., (Jacobson, J. Amer. Chem. Soc. 67, 1996 (1945). To the nitrile (81 g.; 0.72 mole) was added ethylene diamine (43 g.; 0.72 mole). On heating to 90-95 dimethylamine was rapidly evolved to produce N-(flaminoethyl) u-amino isobutyronitrile. This was heated at 160 for hours with thioacetamide to produce the polymer described in Example 1.

EXAMPLE 4 To a stirred solution of ethylene diamine (48 g.; 0.8 mole) in benzene (150 ml.) was added cyclohexanone cyanohydrin 100 g.; 0.8 mole) during 40 minutes. Heat was evolved. The mixture was heated under reflux using a Dean and Stark trap to collect water. After 15 ml. of water had been collected the solvent was removed in vacuo to yield a semi-solid material. 130 g. (98%). This nitrile (40 g.; 24 mole) was heated at 150 for 3 hours with thiourea (400 mg.) while ammonia was evolved. After the addition of 200 mg. thiourea the mixture was heated for a further 10 hours. The product was a dark resinous material which was insoluble in water but readily soluble in isopropanol.

The polymer had the following unit formula EXAMPLE 5 Benzaldehyde cyanohydrin (mandelo nitrile) (134 g.; 1 mole) was reacted with ethylene diamine (60 g. 1 mole) in the manner of the preceding examples. The product was heated in presence of thiourea in the manner described above to produce a polymer with the elimination of ammonia. The polymer was insoluble in water but readily soluble in ethanol, isoprapnol and acetone.

The polymer has the following unit formula EXAMPLE 6 Hexylmethyl ketone cyanohydrin was prepared by reaction of the bisulphite complex with cyanide ion. The cyanohydrin (26 g. 0.19 mole) was reacted with ethylene diamine (11.4 g.; 0.19 mole) and the water produced removed by azeotropic distillation. Heating this adduct with thioacetamide (300 mg.) for 24 hours at -180 brought about complete reaction. The infrared spectrum showed absorption at 6.2 (-C=N) and absence of cyano group. The product was soluble in butanol but insoluble in water.

The polymer has the following unit formula:

The dinitrile (19.4 g.; 0.1 mole) described in Example 7 was heated with triethylene tetramine (14.6 g.; 0.1 mole) and thiourea (400 mg.) for 8 hours at 170-190". The resultant product was a dark oil whose infrared spectrum showed the presence of imidazoline rings and a small amount of unchanged nitrile. A quantitative measure of the ammonia evolved indicated that the reaction was approximately 60% complete.

The polymer has the following unit formula 7 EXAMPLE 9 To cyclohexanone cyanohydrin (50 g.; 0.4 mole) in benzene (100 ml.) was added ethylene diamine (12' g.; 0.2 mole) during 30 minutes. Water (8 ml.) was removed by azeotropie distillation using a Dean and Stark trap for collection. Removal of the solvent in vacuo produced an oily solid (50 g.). Recrystallization from ethanol produced colorless needles, M.P. 123-5 of N,N-bis-(1- cyanocyclohexyl)ethylene diamine. Analysis as follows: C H N requires N, 20.4%, found N, 20.3%. Reaction of this dinitrile with triethylene tetramine in the presence of thiourea in the manner of Example 8, produced the expected polymer by evolution of ammonia.

The polymer has the following unit formula To avoid unnecessary repetition, further non-limiting examples listed in the following table are polymerized by the general procedures outlined above.

The abbreviations in this table have the following meanings:

Ethylene diamine.

- Acetone cyanohydrin.

Hexylmethyl ketone cyanohydrin.

Propylene diamine.

Cyclohexanone cyanohydrin. Triethylene tetramine.

. Diethylene triamine.

. Tetraethylene pentarnine.

ine No.1... A mixture of T.E.I., D.E.T. and T.E.P.

F?? empimogoo ens The corrosion inhibitors contemplated herein find special utility in the prevention of corrosion of pipe or equipment which is in contact with a corrosive oil-containing medium, as, for example, in oil wells producing corrosive oil or oil-brine mixtures, in refineries, and the like. These inhibitors may, however, be used in other systems or applications. They appear to possess properties which impart to metals resistance to attack by a variety of corrosive agents, such as brines, weak inorganic acids, organic acids, CO H 8, etc.

The method of carrying out this process is relatively simple in principle. The corrosion preventive reagent is dissolved in the liquid corrosive medium in small amounts and is thus kept in contact with the metal surface to be protected. Alternatively, the corrosion inhibitor may be applied first to the metal surface, either as is, or as a solution in some carrier liquid or paste. Continuous application, as in the corrosive solution, is the preferred method, however.

The present process finds particular utility in the protection of metal equipment of oil and gas wells, especially those containing or producing an acidic constituent such as H 8, CO organic acids and the like. For the protection of such wells, the reagent, either undiluted or dissolved in a suitable solvent, is fed down the annulus of the well between the casing and producing tubing where it becomes commingled with the fluid in the well and is pumped or flowed from the well with these fluids, thus contacting the inner wall of the casing, the outer and inner wall of tubing, and the inner surface of all wellmotor driven chemical injector pump, or it may be dumped periodically (e.g., once every day or two) into the annulus by means of a so-called boll weevil device or similar arrangement. Where the inhibitor is a solid,

it may be dropped into the well as a solid lump or stock,

it may be blown in as a powder with gas, or it may be Washed in with a small stream of the well fluids or other liquid. Where there is gas pressure on the casing, it is TABLE I Polymerization Example 1st amine Nitrile 2d amine Cat. time, hrs.

10 1 mole P.D 1 mole A.C Thiourea 10 11..-- d 1 mole H.M.C Thioacetamide.- 20 12.. 2 moles C.H.C- 1 mole T.E.T. Thiourea..- 20 13.. Thioacetami e 18 14 Thiourea 20 15 12 16 14 17.. 20 18.... 20 19.. 20 20.. 20 21.. 15 22., 15 23.. 1 mole D.E.I-.. 15 24 1 mole amine N0 20 25 do. 20 26 1 Thi0acetan1ide. 15 1moleT.E.T ..do .d0 16 USE AS CORROSION INHIBITORS This phase of this invention relates to the use of these polymers in inhibiting the corrosion of metals, most particularly iron, steel and ferrous alloys. These polymers can be used in a wide variety of applications and systems where iron, steel and ferrous alloys are affected by corrosion. They may be employed for inhibiting corrosion in processes which require this protective or passivating coating as by dissolution in the medium which comes in contact with the metal. They can be used in preventing atmospheric corrosion, underwater corrosion, corrosion in steam and hot water systems, corrosion in chemical industries, underground corrosion, etc.

necessary, of course, to employ any of these treating methods through a pressure equalizing chamber equipped to allow introduction of reagent into the chamber, equalization of pressure between chamber and casing, and travel of reagent from chamber to well casing.

Occasionally, oil and gas wells are completed in such a manner that there is no opening between the annulus and the bottom of the tubing or pump. This results, for example, when the tubing is surrounded at some point by a packing held by the casing or earth formation below the casing. In such wells the reagent may be introduced into the tubing through a pressure equalizing vessel, after stopping the flow of fluids. After being so treated, the

well should be left closed in for a period of time sufl'icient to permit the reagent to drop to the bottom of the well.

For injection into the well annulus, the corrosion inhibitor is usually employed as a solution in a suitable solvent. The selection of solvent will depend much upon the exact reagent being used and its solubility characteristics.

For treating Wells with packed-off tubing, the use of solid sticks or plugs of inhibitor is especially convenient. These may be prepared by blending the inhibitor with a mineral wax, asphalt or resin in a proportion sufiicient to give a moderately hard and high-melting solid which can be handled and fed into the well conveniently.

The protective action of the herein described reagents appears to be maintained for an appreciable time after treatment ceases, but eventually is lost unless another application is made.

For example, for the protection of gas wells and gascondensate wells, the amount of corrosion inhibitor used might range between about one-half to 3 lbs. per million cubic feet of gas produced, depending upon the amounts and composition of corrosive agents in the gas and the amount of liquid hydrocarbon and water produced. However, in no case does the amount of inhibitor required appear to be stoichiometrically related to the amount of acids produced by a well, since protection is obtained with much less corrosion inhibitor than usually would be required for neutralization of the acids produced.

These compositions are particularly effective in the prevention of corrosion in systems containing a corrosive aqueous medium, and most particularly in systems containing brines.

These polymeric reagents can also be used in the prevention of corrosion in the secondary recovery of petroleum by watter flooding and in the disposal of waste water and brine from oil and gas wells. Still more particularly, they can be used in a process of preventing corrosion in water flooding and in the disposal of waste water and brine from oil and gas wells which is characterized by injecting into an underground formation an aqueous solution containing minor amounts of the compositions of this invention, in sufficient amounts to prevent the corrosion of metals employed in such operation.

When an oil well ceases to flow by the natural pressure in the formation and/ or substantial quantities of oil can no longer be obtained by the usual pumping methods, various processes are sometimes used for the treatment of the oil-bearing formation in order to increase the flow of oil. These processes are usually described as secondary recovery processes. One such process which is used quite frequently is the water flooding process wherein water is pumped under pressure into what is called an injection well and oil, along with quantities of water, that have been displaced from the formation, are pumped out of an adjacent well usually referred to as a producing well. The oil which is pumped from the producing well is then separated from the water that has been pumped from the producing well and the water is pumped to a storage reservoir from which it can again be pumped into the injection well. Supplementary water from other sources may be used in conjunction with the produced water. When the storage reservoir is open to the atmosphere and the oil is subject to aeration this type of water flooding system is referred to herein as an open Water flooding system. If the water is recirculated in a closed system without substantial aeration, the secondary recovery method is referred to herein as a closed water flooding system.

Because of the corrosive nature of oil field brines, to economically produce oil by water flooding, it is necessary to prevvent or reduce corrosion since corrosion increases the cost thereof by making it necessary to repair and replace such equipment at frequent intervals.

We have discovered a method of preventing corrosion in systems containing a corrosive aqueous media, and

10 most particularly in systems containing brines, which is characterized by employing the polymers described herein. For example, we have discovered an improved process of protecting from corrosion metallic equipment employed in secondary oil recovery by water flooding such as injection wells, transmission lines, filters, meters, storage tanks, and other metallic implements employed therein and particularly those containing iron, steel, and ferrous alloys, such process being characterized by employing in water flood operation an aqueous solution of the compositions of this invention.

The invention, then, is particularly concerned with preventing corrosion in a water flooding process characterized by the flooding medium, containing an aqueous or an oil field brine solution of these polymers.

In many oil fields large volumes of water are produced and must be disposed of where water flooding operations are not in use or where water flooding operations cannot handle the amount of produced water. Most States have laws restricting pollution of streams and land with produced waters, and oil producers must then find some method of disposing of the waste produced salt water. In many instances therefore, the salt water is disposed of by injecting the water into permeable low pressure strata below the fresh water level. The formation into which the Water is injected is not the oil producing formation and this type of disposal is defined as salt water disposal or waste water disposal. The problems of corrosion of equipment are analogous to those encountered in the secondary recovery operation by water flooding.

The polymers of this invention can also be used in such water disposal wells thus providing a simple and economical method of solving the corrosion problems encountered in disposing of unwanted water.

Water flood and waste disposal operations are too well known to require further elaboration. In essence, the flooding operation is effected in the conventional manner except that the flooding medium contains a minor amount of these polymers, sutficient to prevent corrosion.

While the flooding medium employed in accordance with the present invention contains water or oil field brine and the polymers of this invention, the medium may also contain other materials. For example, the flooding medium may also contain other agents such as surface active agents or detergents which aid in wetting throughout the system and also promote the desportion of residual oil from the formation, sequestering agents which prevent the deposition of calcium and/or magnesium compounds in the interstices of the formation, bacteriocides which prevent the formation from becoming plugged through bacterial growth, tracers, etc. Similarly, they may be employed in conjunction with any of the operating techniques commonly employed in water flooding, periph eral flooding, etc. and and in conjunction with other secondary recovery methods.

The concentration of the corrosion inhibitors of this invention will vary widely depending on the particular polymer, the particular system, etc. Concentrations of at least about 0.25 p.p.m., such as about 0.75 to 7,500 p.p.m. for example about 1 to 5,000 p.p.m., advantageously about 10 to 1,000 p.p.m., but preferably about 15-250 p.p.m. may be employed. Larger amounts can also be employed such as 1.5-5.0% although there is generally no commercial advantage in so doing.

For example, since the success of a water flooding operation manifestly depends upon its total cost being less than the value of the additional oil recovered from the oil reservoir, it is quite important to use as little as possible of these compounds consistent with optimum corrosion inhibition. Since these compounds are themselves inexpensive and are used in low concentrations, they enhance the success of a flood operation by lowering the cost thereof.

By varying the constituents of the composition, the compounds of this invention can be made more oil or more water soluble, depending on whether the composition is to be employed in oil or water systems.

Although the manner of practicing the present invention is clear from the foregoing description, the following non-limiting specific examples are included for purposes of illustration.

The results obtained are presented in the following Table II.

All of the compositions prepared in Table I, Examples 1-27, are excellent corrosion inhibitors when tested and compared with the commercial corrosion inhibitors previously selected as the best commercial inhibitors for the corrosion system. The following examples are presented as exemplary.

TABLE II Percent protection at-- 3 3 3 3 3 Blank ppm. ppm. p.p.m. p.p.m. p.p.m. wt. loss Example 1 92 94 92 91 99 0.185 Commercial inhibitor 47 46 49 41 46 O. 185

Percent protection at-- 4 8 16 22 p.p.m. p.p.m. p.p.m. p.p.m.

Example 2 94 96 96 .296 Commercial inhibitor 70 76 S7 92 296 Percent protection at- 8 16 22 ppm. p.p.m. ppm.

Example 6 2A 92 92 346 Commercial inhibitor 22 71 98 .346

Percent protection at- 4 8 16 32 p.p.m. p.p.m. p.p.m. ppm.

Example 8 64 80 85 157 Commercial inhibitor 31 58 69 157 EXAMPLES These polymers can also be employed in conjunction These tests were run under conditions so set up as to simulate those found in an actual producing Well. The test procedure involved the measurement of the corrosive action of fluids inhibited by the compositions herein described upon sandblasted SAE 1020 steel coupons measuring A inch in diameter and being 4 inches long when compared to test coupons containing no inhibitor and commercial inhibitors.

Clean pint bottles were half-filled (almost 200 ml.) with sea-water (i.e., tap water containing 3% by weight of the salts, magnesium chloride, calcium chloride, sodium sulfate and sodium chloride) which had been saturated with hydrogen sulfide. Those requiring inhibitor were charged with the same by pipetting calculated amounts contained in suitable solvents (water, isopropyl alcohol, mineral spirits) to give the required parts per million of inhibitor. Uninhibited blanks were run in conjunction with inhibited solutions. The bottles were now filled (total volume now above 400 ml.) leaving a small air space to allow expansion. The weighed coupons attached to sealing caps were screwed onto the bottles and they were placed on a rotating wheel for seven days at 115 F. The coupons were then removed, cleaned electrolytically in sulfuric acid (using the coupons as a cathode) and washed successively with dilute sodium hydroxide, twice with water, once with acetone and finally dried.

When the inhibitor was oil-soluble as contrasted to water-soluble, a two-phase system was used instead of the all brine system and this simply consisted of using hydrogen sulfide saturated mineral spirits to replace by volume of the brine.

The changes in the weights of the coupons during the corrosion test were taken as a measurement of the effectiveness of the inhibitor compositions. Protective percentage was calculated for each test coupon taken from the inhibited fluids in accordance with the following formula:

from uninhibited fluids and W is the loss in weight of coupons which were subjected to inhibited fiuids.

X 100 percent protection with other corrosion inhibitors, for example, of the filmforming type. Non-limiting examples include the acylated polyamines such as described in U.S. Pats. Re. 23,227, 2,466,517, 2,468,163, 2,598,213 and 2,640,029. These acylated polyamines may be described as amides, imidazolines, tetrahydropyrimidines, etc.

BREAKING OIL-IN-WATER EMULSIONS The polymers of this invention can also be used in a process for resolving or separating emulsions of the oil-inwater class, by subjecting the emulsion to these polymers.

Emulsions of the oil-in-water class comprise organic oily materials, which, although immiscible with water or aqueous or non-oily media, are distributed or dispersed as small drops throughout a continuous body of non-oily medium. The proportion of dispersed oily material is in many and possibly most cases a minor one.

Oil-field emulsions containing small proportions of crude petroleum oil relatively stably dispersed in water or brine are representative oil-in-water emulsions. Other oil-inwater emulsions include: steam cylinder emulsions, in which traces of lubricating oil are found dispersed in condensed steam from steam engines and steam pumps, wax-hexane-water emulsions, encountered in de-waxing operations in oil refining; butadiene tar-in-water emulsions, in the manufacture of butadiene from heavy naphtha by cracking in gas generators, and occurring particularly in the wash box waters of such systems; emulsions of flux oil in steam condensate produced in the catalytic dehydrogenation of butylene to produce butadiene; styrenein-water emulsions, in synthetic, rubber plants, synthetic latex-in-water emulsions, in plants producing copolymer butadiene-styrene or GRS synthetic rubber; oil-in-water emulsions occuring in the cooling water systems of gasoline absorption plants; pipe press emulsions from steamactuated presses in clay pipe manufacture; emulsions of petroleum residues-in-diethylene glycol, in the dehydration of natural gas.

In other industries and arts, emulsions of oily materials in water or other non-oily media are encountered, for example, in sewage disposal operations, synthetic resin emulsions paint formulation, milk and mayonnaise processing, marine ballast water disposal, and furniture 13 polish formulation. In cleaning the equipment used in processing such products, diluted oil-in-water emulsions are inadvertently, incidentally, or accidentally produced. The disposal of aqueous wastes is, in general, hampered by the presence of oil-in-water emulsions.

Essential oils comprise non-saponifiable materials like terpenes, lactones, and alcohols. They also contain saponifiable esters or mixtures of saponifiable and non-saponifiable materials. Steam distillation and other production procedures sometimes cause oil-in-water emulsions to be produced, from which the valuable essential oils are difficult to recover.

In all such examples, a non-aqueous or oily material is emulsified in an aqueous or non-oily material with which it is naturally immiscible. The term oil is used herein to cover broadly the water-immiscible materials present as dispersed particles in such systems. The nonoily phase obviously includes diethylene glycol, aqueous solutions, and other non-oily media in addition to water itself.

The foregoing examples illustrate the fact that, within the broad genus of oil-in-water emulsions, there are at least three important sub-genera. In these, the dispersed oily material is respectively non-saponifiable, saponifiable, and a mixture of non-saponifiable and saponifiable materials. Among the most important emulsions of nonsaponifiable material in water are petroleum oil-in-water emulsions. Saponifiable oil-inwater emulsions have dispersed phases comprising, for example, saponifiable oils and fats and fatty acids, and other saponifiable oily or fatty esters and the organic components of such esters to the extent such components are immiscible with aqueous media. Emulsions produced from certain blended lubricating compositions containing both mineral and fatty oil ingredients are examples of the third sub-genus.

Oil-in-water emulsions contain widely different proportions of dispersed phase. Where the emulsion is a waste product resulting from the flushing with water of manufacturing areas or equipment, the oil content may be only a few parts per million. Resin emulsion paints, as produced, contain a major proportion of dispersed phase. Naturally-occurring oil-field emulsions of the oilin-water class carry crude oil in proportions varying from a few parts per million to about 20%, or even higher in rare cases.

The present invention is concerned with the resolution of those emulsions of the oil-in-water class which contain a minor proportion of dispersed phase, ranging from 20% down to a few parts per million. Emulsions containing more than about 20% of dispersed phase are commonly of such stability as to be less responsive to the present polymers, possibly because of the appreciable content of emulsifying agent present in such systems, whether intentionally incorporated for the purpose of stabilizing them, or not.

Although the present invention relates to emulsions containing as much as 20% dispersed oily material, many if not most of them contain appreciably less than this proportion of dispersed phase. In fact, most of the emulsions encountered in the development of this invention have contained about 1% or less of dispersed phase. It is to such oil-in-Water emulsions having dispersed phase volumes of the order of 1% or less to which the present process is particularly directed. This does not mean that any sharp line of demarcation exists and that, for example, an emulsion containing 1.0% of dispersed phase will respond to the process, Whereas one containing 1.1% of the same dispersed phase will remain unaffected; but that, in general, dispersed phase proportions of the order of 1% or less appear most favorable for application of the present process.

In emulsions having high proportions of dispersed phase, appreciable amount of some emulsifying agent are probably present, to account for their stability. In the case of more dilute emulsions, containing 1% or less of dispersed phase, there may be difficulty in accounting for their stability on the basis of the presence of an emulsifying agent in the conventional sense. For example, steam condensate frequently contains very small proportions of refined petroleum lubricating oil in extremely stable dispersion; yet neither the steam condensate nor the refined hydrocarbon oil would appear to contain anything suitable to stabilize the emulsion. In such cases, emulsion stability must probably be predicated on some basis other than the presence of an emulsifying agent.

The present process, as stated above, appears to be effective in resolving emulsions containing up to about 20% of dispersed phase. It is particularly effective on emulsions containing not more than 1% of dispersed phase, which emulsions are the most important, in view of their common occurrence.

The present process is not believed to depend for its effectiveness on the application of any simple laws, because it has a high level of effectiveness when used to resolve emulsions of widely different composition, e.g., crude or refined petroleum in water or diethylene glycol, as well as emulsions of oily materials like animal or vegetable oils or synthetic oily materials in water.

Some emulsions are by-products of manufacturing procedures in which the composition of the emulsion and its ingredients is known. In many instances, however, the emulsions to be resolved are either naturally-occurring or are accidentally or unintentionally produced; or in any event they do not result from a deliberate or premeditated emulsification procedure. In numerous instances, the emulsifying agent is unknown and as a matter of fact an emulsifying agent, in the conventional sense, may be felt to be absent. It is obviously very difiicult or even impossible to recommend a resolution procedure for the treatment of such latter emulsions on the basis of theoretical knowledge. Many of the most important applications of the present process are concerned with the resolution of emulsions which are either naturally-occurring or are accidentally, unintentionally, or unavoidably produced. Such emulsions are commonly of the most dilute type, containing about 1% or less of dispersed phase, although concentrations up to 20% are herein included, as stated above.

The process which constitutes the present invention consists in subjecting an emulsion of the oil-in-water class to the action of the polymer of the kind described, thereby causing the oil particles in the emulsion to coalesce sufficiently to rise to the surface of the non-oily layer (or settle to the bottom, if the oil density is greater), when the mixture is allowed to stand in the quiescent state after treatment with the polymer reagent or demulsifier.

Applicability of the present process can be readily determined by direct trial on any emulsion, without reference to theoretical considerations. This fact facilitates its application to naturally-occurring emulsions, and to emulsions accidentally, unintentionally, or unavoidably produced; since no laboratory experimentation, to discover the nature of the emulsion components or of the emulsifying agent, is required.

The present reagents are useful because they are able to recover the oil from oil-in-water class emulsions advantageously and at low cost. In some instances, they have been found to resolve emulsions which are not economically or effectively resolvable by any other known means.

These polymeric reagents are useful in undiluted form or diluted with any suitable solvent. Water is commonly found to be a highly satisfactory solvent, because of its ready availability and negligible cost; but in some cases, non-aqueous solvents such as aromatic petroleum solvent may be found preferable. The products themselves may exhibit solubilities ranging from rather modest waterdispersibility to full and complete dispersibility in that solvent. Because of the small proportions in which our reagents are customarily employed in practicing our process, apparent solubility in bulk has little significance. In the extremely low concentrations of use they undoubtedly 15 exhibit appreciable water solubility of water-dispersibility as well as oil-solubility or oil-dispersibility.

These polymeric reagents may be employed alone, or they may in some instances be employed to advantage admixed with other and compatible oil-in-water demulsifiers.

This process is commonly practiced simply by introducing sufficient but minor proportions of the polymer into an oil-in-water class emulsions, agitating to secure distribution of the reagent and incipient coalescence, and letting stand until the oil phase separates. The proportion of polymer required will vary with the character of the emulsion to be resolved. Ordinarily, proportions of reagent required are from about .005 p.p.m.-l0,000 p.p.m. such as 1l,000 p.p.m., for example about 3-300 p.p.m., but preferably 5-50 p.p.m., based on the volume of emulsions treated, but more is sometimes required. Since the economics of the process are important, no more is employed than is required for effective separation. It has been found that such factors as the nature of the particular polymer, feed rate, agitation and settling time are somewhat interrelated. For example, if suflicient agitation of proper character is employed, the settling time is shortened materially. On the other hand, if satisfactory agitation is not available, but extended settling time is, the process is equally productive of satisfactory results.

Agitation may be achieved by any available means. In many cases, it is sufficient to introduce the polymeric reagent into the emulsion and use the agitation produced as the latter flows through a conduit or pipe. In some cases, agitation and mixing are achieved by stirring together or shaking together the emulsion and polymer. In some instances, distinctly improved results are obtained by the use of air or other gaseous medium. Where the volume of gas employed is relatively small and the conditions of its introduction relatively mild, it behaves as a means of securing ordinary agitation. Where aeration is effected by introducing a gas directly under pressure or from porous plates or by means of aeration cells, the effect is often importantly improved, until it constitutes a difference in kind rather than degree. A sub-aeration type flotation cell, of the kind commonly employed in ore beneficiation operations, is an extremely useful adjunct in the application of these polymer reagents to many emulsions. It frequently accelerates the separation of the emulsion, reduces reagent requirement, or produces an improved eflluent. Sometimes all three improvements are observable.

Heat is ordinarily of little importance in resolving oilin-water class emulsions with our reagents. Still there are some instances where heat is a useful adjunct. This is especially true where the viscosity of the continuous phase of the emulsion is appreciably higher than that of water.

In some instances, importantly improved results are obtained by adjusting the pH of the emulsion to be treated, to an experimentally determined optimum value.

The polymeric reagent feed rate also has an optimum range, which is sufficiently wide, however, to meet the tolerances required for the variances encountered daily in commercial operations. A large excess of reagent can produce distinctly unfavorable results.

The manner of practicing the present invention is clear from the foregoing description. However, for completeness the following non-limiting specific examples are included for purposes of illustration.

An oil-in-water petroleum emulsion was treated as follows:

A series of four bottles of the emulsion were treated with the polymeric reagents in the following concentrations 30, 15, 7.5 and 3.75 p.p.m., based on the emulsion. A commercial oilin-water demulsifier was run as a control and at the same concentrations as the polymeric reagent after sufficient agitation, in the form of 130 shakes per minute for 5 minutes. The bottles were observed and comparisons drawn between the effect of the polymeric reagent and the commercial demulsifier as to which gave the clear water layer.

In all cases employing the polymeric reagents of Table I, it was found that the polymeric reagents of this invention were superior to the commercial demulsifier. After selecting the demulsifier by the above procedure, the demulsifier is employed in a commercial application. The following illustrates commercial applications of this invention, employing the compounds of Table I, Examples 1-27.

Commercial Example A This process is practiced on location by flowing the well fluids, consisting of free crude oil, oil-in-water emulsion, and natural gas, through a gas separator, then to a steel tank of 5,000-barrel capacity. In this tank, the oil-in-water emulsion falls to the bottom and is so separated from the free oil. The oil-in-water emulsion is withdrawn from the bottom of this tank, and the demulsifier selected is introduced into the stream at this point. Depending on the emulsion, the proper proportion of demulsifier is employed.

The chemicalized emulsion flows to a second tank, mixing being achieved in the pipe. In the second tank it is allowed to stand quiescent. Clear water is withdrawn from the bottom of this tank, separated oil from the top.

Commercial Example B This is an example of the application of the aeration step in our process. The emulsion is a naturally-occurring petroleum oil-in-water emulsion. It is placed in a sub-aeration flotation cell of the type commonly employed in the ore beneficiation industry. The stirring mechanism is started to begin introduction of the air, and at the same time the mixture of the selected demulsifier is added in the proper proportions of demulsifier to emulsion. Clear examples are taken from the bottom of the machine.

This example illustrates the beneficial influence of the aeration technique. In most cases, it accelerates separation. In some, it permits use of smaller proportions of reagent; but in some cases, it achieves resolution, whereas, in absence of its use, satisfactory separation may not be achieved in reasonable time with reasonable reagent consumption.

These reagents have likewise been successfully applied to other oil-in-water class emulsions, of which representative examples have been referred to above. Their use is, therefore, not limited to crude petroleum-in-water emulsions.

WATER CLARIFICATION The present invention also relates to a method for the clarification of water containing suspended matter.

Accordingly clarification of water containing suspended particles of matter is effected by adding to such water polymers of this invention.

Water containing suspended particles which may be treated by the present invention may have its origin either in natural or artificial sources, including industrial and sanitary sources. Waters containing suspended particles of nautral origin are usually surface waters, wherein the particles are suspended soil particles (silt), although sub-surface waters may also be treated according to the present invention. Water having its origin in industrial process (including sanitary water) operations may contain many different varieties of suspended particles. These particles are generally the result of the particular industrial or sanitary operation concerned. Prior to discharging such industrial waste waters into natural water courses it generally is desired that the suspended matter be removed.

The present process may likewise be applied to water contained in stock or fish ponds, lakes or other natural or artificial bodies of water containing suspended solids. It may be applied to industrial water supplied either in preparation therefor, during or after use and prior to disposal. It may be applied to sanitary water supplies 17 either for the elimination of suspended solids prior to use for such purposes, or it may be applied to such waters which have become contaminated with impurities from any source.

Most naturally occurring waters contain an amount of simple electrolytes (sodium, potassium, ammonium, calcium, aluminum salts, etc.) in excess of that necessary for the initial aggregation of the ultimate silt particles. This is likewise true of particles of suspended material in industrial or sanitary waters. The ultimate particles of silt or other materials are therefore naturally somewhat aggregated by reason of the presence of such electrolytes. However, the forces binding such ultimate particles together are not great and moreover are not such as to generally effect either rapid settling rates of the flocculated material or strong enough to prevent deflocculation.

The polymer of this invention causes rapid flocculation and also reinforces the formed aggregates of particles causing a general tightening or bonding together of the initial particles and an increased rate of coagulation and settling. thus forming a less turbid supernatant liquid.

The addition of the polymers of this invention to the water suspension should be made in such a fashion that the resulting flocculation and aggregation of the particles takes place uniformly throughout the body of water. In order to obtain a uniform addition of the compositions of the invention to the water-borne suspension it is generally desirable to prepare a relatively dilute stock solution of the polymer compositions and then to add such solutions to the body of water in the proportions indicated above. Clarification may take place either in the natural body of water or it may be caused to take place in hydraulic thickeners of known design.

The amount of polymeric compositions to be employed will vary depending upon the amount and the degree of subdivision of the solids to be agglomerated or fiocculated, the chemical nature of such solid and the particular inventive compositions employed. In general, one employs at least a sufiicient amount of the polymeric compositions to promote flocculation. In general, one employs 0.005- 10,000 p.p.m. or more such as about 0.5-l,000 p.p.m., for example about 1-500 p.p.m., but preferably about 2-5 p.p.m. Since the economics of these processes are important, no more than the minimum amount required for efficient removal is generally employed. It is desired, of course, to employ sufiicient polymeric compositions so flocculation will take place without causing the formation of stable dispersions.

The precipitating action of the polymeric compositions can be employed in the application of loading or filling materials to textiles or paper.

In the processing of fine mineral particles in aqueous suspension the polymeric composition flocculating agents will be especially useful. In the processing of ores to separate valuable mineral constituents from undesirable matrix constituents, it is frequent practice to grind the ore into a finely-divided state to facilitate separation steps such as selective flotation and the like. In many ore dressing procedures, the finely-divided ore is suspended in water to form a pulp or slime. After processing, it is usually desirable to dewater the pulps or slimes either by sedimentation or filtering. In such operations, certain ores are particularly troublesome in that the finely-divided ore, when suspended in water, forms stable slime which settles very slowly, if at all. Such slimes are unsuitable for concentration or dewatering by sedimentation and are difficult to dewater by filtration because of the tendency to clog the pores of the filter, thus leading to excessively time-consuming and inefiicient operation of the filters. In some cases, for example, in certain phosphate mining operations, the formation of very stable suspensions of finelydivided mineral results not only in the loss of considerable valuable minerals as waste but also requires large expenditures for the maintenance of holding ponds for the waste. Similar problems are involved in processing gold, copper, nickel, lead, zinc, iron, such as taconite ores, uranium and other ores, and the inventive flocculating agents will be useful in these operations.

Some specific additional applications for the polymeric composition of this invention, not intended to be limiting but merely illustrative are listed below. The polymeric composition can be used for the clarification of beers or wines during manufacture. Another use is in processing effluents in pharmaceutical operations for the recovery of valuable products or removal of undesirable by-products. A particularly important use for these polymeric flocculating agents is in the clarification of both beet sugar and cane sugar juices in their processing. Still another use is for flocculation and recovery of pigments from aqueous suspensions thereof. The polymeric composition will be particularly useful in sewage treatment operations as a flocculating agent. A further use is to promote by fiocculation the removal of coal from aqueous suspensions thereof. In other words, the polymeric flocculating agents of the invention are generally useful for processing aqueous efliuents of all types to facilitate the removal of suspended solids.

A water soluble or water dispersible polymer, to the extent of efi'ective concentration, is employed.

These compositions can also be employed in the process of flocculating white water and/or recycling of the precipitate solids in the paper making process described in US. application Ser. No. 347,023, filed Feb. 24, 1964, now US. Pat. No. 3,393,157, and other processes described therein.

Although the manner of practicing the present invention is clear from the foregoing description, the following non-limiting specific examples are included for purposes of illustration.

Naturally occurring water from many sources, and in some instances, brine and brackish waters are used in the recovery of petroleum by secondary water-flooding operations. Clarification of the water is necessary in many instances prior to water flooding because the suspended impurities tend to plug the underground formations into which waters are pumped.

EXAMPLES A suspension of FeS in brine was subjected to the action of the water-soluble polymers prepared herein.

In these tests, the FeS concentration is 25 parts per million and 1% and 5% brine solution were used. Metered quantities (500 ml.) of the homogeneous suspension were placed into 1000 ml. beakers and stirred at r.p.m. The polymer to be tested was injected into the suspension to give final active concentrations varying between 2 through 4 parts per million. A commercial flocculant was run simultaneously at equivalent concentrations for comparison and the stirring was achieved by use of a Phipp and Bird floc multi-stirrer. After one minute the stirring rate was reduced to 20 to 30 rpm. and maintained thus for ten minutes. At this time the stirring was stopped. The evaluation of the polymer started at the moment of flocculation and continued with respect to the floc size and rate of precipitation. The final evaluation was achieved by visual examination of the color of the resultant aqueous phase.

The results obtained by employing the polymers, Examples 1-27 of Table I, are found to be superior to the commercial flocculating agent usually employed.

These polymers are also effective in flocculating the other systems described herein.

The following is a partial list of industry systems in which the polymers of the present invention can be employed as flocculating agents.

(1) Petroleum industry (2) Food industry such as in the dairy industry, the canning, freezing and dehydration industries (3) Metal plating industry (4) Chemical and pharmaceutical industries Mining industry, for example, in the phosphate mining industry such as in phosphate slirnes (6) Fermentation industries, such as in alcohol, beer,

yeast, antibiotics, etc. production (7) Tanning industry (8) Meat packing and slaughter house industry (9) Textile industry Sugar refining industry 11) Coal industry (12) Soap industry (13) Sewage purification (14) Corn starch industry Fat processing and soap industry (16) Paper industry (17) Hydroelectric plants, atomic energy operations,

boiler plants, etc.

OTHER DERIVATIVES These products may be further reacted to form derivatives thereof, for example, they may be oxyalkylated with alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, octylene oxide, alone or in combination; with styrene oxide, glycide, methyl glycide, allyl glycidyl ether, glycidyl isopropyl ether, glycidyl phenylether, diepoxides, polyepoxides, etc.

The may be reacted with alkylene irnines such as ethyleneimine, propylene imine, etc., dialkylaminoepoxypropane of the structure where the Rs are alkyl, etc.

They may be acylated with monocarboxylic acids, such as aromatic acids, fatty acids, aliphatic acids, etc. and polycarboxylic acids, aliphatic dicarboxylic acids, aromatic dicarboxylic acids for example diglycollic, phthalic, succinic, etc., acids.

These compounds may also be treated With more than one agent, for example, they may be partially acylated, then oxyalkylated, partially oxyalkylated then acylated, etc.

Salts may be formed of these polymers as derivatives for example salts of either organic or inorganic acids such as acetic acid, glycollic acid, fatty acids, benzoic acid, etc. HCl, sulfuric acids, etc.

OTHER USES In addition to the uses described above, these compositions and/or derivatives thereof, can be used as follows:

(1) as demulsifiers for oil-in-water emulsions (2) as biocides i.e. bacteriocides, algicides, etc.

(3) as additives to various petroleum fuels including gasoline, diesel fuel, jet fuels, etc.

(4) as gasoline anti-icers and anti-stallers (5) as flotation agents, such as flotation collection agents (6) as asphalt emulsifiers and anti-stripping agents for asphalt-mineral aggregate compositions (7) as emulsifiers, for example, in metal cleaners, auto polishes, wax emulsions, etc.

(8) as additives for sludging oil and cutting oils (9) as fuel dehazing agents (10) as agents for preparing emulsions for the hydrofrac process of enhancing oil recovery (11) as agents to prepare polymer emulsions (12) as agents of solvents to inhibit parafiin deposition 13) as agents for the textile industry such as mercerizing assistants, wetting agents, rewetting agents, penetrating agents, dispersing agents, softening agents, dyeing assistants, etc.

(14) as anti-static agents for textile, plastics, etc.

(15) as agents in leather processing 16) as lube oil additives (17) as emulsifiers for insecticidal and agricultural compositions (18) as additives for rubber latices, for example, to prevent acid coagulation (19) as additives in the production of latex foam rubber, for example, as gel sensitizers and processing aids in the manufacture of foam rubber (20) as additives for pigment dispersion in various applications such as paints, plastic, rubber, etc.

(21) as additives for primer paints to help insure adhesion to metallic surfaces (22) as additives useful as a freeze-thaw stabilizer for latex-base paints (23) as agents for the pulp and paper industry, such as sizing aids, etc.

(24) general metal deactivators.

We claim:

1. A process of inhibiting corrosion of metals by a corrosive medium comprising keeping in contact with the surface of the metal to be protected, a corrosion inhibiting amount of a polymer of 2-100 recurring units, the recurring structural unit being Z is selected from the group consisting of A and H lg n is from 0 to 9 and n is from 1 to 9.

2. The process of claim 1 wherein the recurring structural unit is 3. The process of claim 1 wherein the recurring structural unit is r I l 21 4. The process of claim 1 wherein the recurring structural unit is 5. The process of claim 1 wherein the recurring struc tural unit is 6. The process of claim 1 wherein the recurring structural unit is 22 8. The process of claim 7 wherein R is C H and A is CH CH 9. The process of claim 7 wherein R is CH 10. The process of claim 9 wherein A is -CH CH References Cited UNITED STATES PATENTS 2,793,997 5/1957 Hughes 212.7 X 2,836,557 5/1958 Hughes 212.7 X 2,836,558 5/1958 Hughes 21-2.7 X 2,865,817 12/1958 Clausen 212.7 UX 2,889,193 6/1959 Denman et a1. 212.7 2,889,334 6/1959 Hughes 212.7 X 3,247,094 4/1966 Dajani 212.7 X 3,514,251 5/ 1970 Annand et a1. 212.5

BARRY S. RICHMAN, Primary Examiner U.S. Cl. X.R. 

